Optical module and optical recording and/or reproducing apparatus

ABSTRACT

An optical module has a first light source which emits a first light beam from a first light emission point in a predetermined direction, a second light source which emits a second light beam from a second light emission point in the predetermined direction, and an optical element. The optical element includes a plurality of reflection surfaces for reflecting the first and second light beams, and finally outputting the first and second light beams in the predetermined direction with a separation between the first and second light beams smaller than a distance between the first and second light emission points.

BACKGROUND OF THE INVENTION

This application claims the benefit of Japanese Patent Applications No.2001-083606 filed Mar. 22, 2001, No. 2001-170357 filed Jun. 6, 2001, No.2001-206358 filed Jul. 6, 2001, No. 2001-282328 filed Sep. 17, 2001, andNo. 2002-030147 filed Feb. 6, 2002, in the Japanese Patent Office, thedisclosures of which are hereby incorporated by reference.

1. Field of the Invention

The present invention generally relates to optical modules and opticalrecording and/or reproducing apparatuses, and more particularly to anoptical module which is usable as a light source for generating lightbeams, and an optical recording and/or reproducing apparatus whichrecords information on and/or reproduces information from a recordingmedium using the light beams generated from such an optical module.

An optical module of an optical pickup generates a light beam from asemiconductor laser. The light beam is used to record information onand/or reproduce information from optical recording media which includeoptical disks such as a compact disk (CD) and high-density optical diskssuch as a digital versatile disk (DVD).

2. Description of the Related Art

Recently, various kinds of optical recording media, including opticaldisks and high-density optical disks, have been proposed. The opticaldisks include the CD, CD-R and CD-RW. On the other hand, thehigh-density optical disks include the DVD and S-DVD. Ideally, it isdesirable for a single optical recording and/or reproducing apparatus tobe able to recording information on and/or reproduce information from aplurality of kinds of optical disks.

However, an optical pickup which is used for the recording and/orreproduction of information using the optical disk such as the CD, CD-Rand CD-RW generates a light beam having a wavelength of 780 nm. A beamspot of this light beam cannot be converged to the size of a pit formedon the high-density optical disk such as the DVD and S-DVD.

On the other hand, an optical pickup which is used for the recordingand/or reproduction of information using the high-density optical disksuch as the DVD and S-DVD generates a light beam having a wavelength of650 nm. But a pigment used in the optical disk such as the CD-R cannotreflect this light beam and thus light beam will be transmitted throughthe optical disk such as the CD-R, thereby making it impossible toreproduce the information from the optical disk such as the CD-R.

Therefore, in order to record information on and/or reproduceinformation from the optical disk such as the CD-R and the high-densityoptical disk such as the DVD using a single optical recording and/orreproducing apparatus, it is necessary to provide two semiconductorlasers in the light source part of the optical pickup to respectivelygenerate the light beams having the wavelengths of 780 nm and 650 nm.

But in order to use a common optical system for the two light beamswhich have the wavelengths of 780 nm and 650 nm and are generated fromthe two semiconductor lasers, it is necessary to set the two lightemission points close together as much as possible. Accordingly, asemiconductor laser unit has been proposed, in which a semiconductorlaser chip for generating the light beam having the wavelength of 650 nmand a semiconductor laser chip for generating the light beam having thewavelength of 780 nm are arranged horizontally on a single package.However, according to this proposed semiconductor laser unit, thelocation of the light emission points are affected by the width of eachsemiconductor laser chip and the width of a sub-mounting member, and aninterval of the light emission points of the two semiconductor laserchips becomes approximately 300 μm to 400 μm and large. As a result, itbecomes extremely difficult to design the optical system of the opticalpickup.

Hence, a method of artificially reducing the interval between the twolight emission points using reflection surfaces has been proposed in aJapanese Laid-Open Patent Application No. 11-39684, for example. FIG. 1is a diagram showing an optical module employing this proposed method,and corresponds to FIG. 2 of the Japanese Laid-Open Patent ApplicationNo. 11-39684. In FIG. 1, a part surrounded by a dotted line is shown onan enlarged scale on the right portion of this figure. A detaileddescription of FIG. 1 will be omitted in this specification, because itis described in the Japanese Laid-Open Patent Application No. 11-39684.

As shown in FIG. 1, a sub-mounting member 32A has a triangular crosssection with reflection surfaces 32B and 32C. A laser beam B1 outputfrom a semiconductor laser 34 is reflected by the reflection surface32B, and a laser beam B2 output from a semiconductor laser 36 isreflected by the reflection surface 32C. Because the laser beams B1 andB2 are reflected and bent by the reflection surfaces 32B and 32C, it ispossible to artificially reduce the interval between the two lightemission points. In FIG. 1, a reference numeral 30 denotes a supportplate, a reference numeral 32 denotes a support body, and a referencenumeral 38 denotes a cap.

In order to realize the method proposed in the Japanese Laid-Open PatentApplication No. 11-39684, it is necessary to provide the sub-mountingmember 32A having the triangular cross section. However, it is difficultto accurately form the sloping surfaces of the sub-mounting member 32Ahaving the triangular cross section, particularly when the inclinationangle of the sloping surfaces is 45 degrees. Because the slopingsurfaces determine the reflection surfaces 32B and 32C, inaccuratesloping surfaces cause inaccurate reflections at the reflection surfaces32B and 32C.

Although several techniques have been proposed to make a member having atriangular cross section with sloping surfaces having an inclination of45 degrees, none are actually capable of stably mass-producing themember with a high accuracy. Alternatively, it is conceivable to usemicroprisms to realize a member having the triangular cross section, butit would be extremely difficult to accurately mount the microprisms.Furthermore, since the use of the microprisms will make the memberexpensive, the use of such a member in the optical pickup will make theoptical pickup too expensive from the practical point of view.

Accordingly, the proposed method of artificially reducing the intervalbetween the two light emission points using the reflection surfacesrequire parts which are both expensive and unsuited for mass-production.

SUMMARY OF THE INVENTION

Accordingly, it is a general object of the present invention to providea novel and useful optical module and optical recording and/orreproducing apparatus, in which the problems described above areeliminated.

Another and more specific object of the present invention is to providean optical module and an optical recording and/or reproducing apparatus,which can artificially reduce an interval between two light emissionpoints using a structure which is both inexpensive and suited formass-production.

Still another object of the present invention is to provide an opticalmodule comprising a first light source which emits a first light beamfrom a first light emission point in a predetermined direction, a secondlight source which emits a second light beam from a second lightemission point in the predetermined direction, and an optical elementhaving a plurality of reflection surfaces for reflecting the first andsecond light beams, and finally outputting the first and second lightbeams in the predetermined direction with a separation between the firstand second light beams smaller than a distance between the firsthandsecond light emission points. According to the optical module of thepresent invention, it is possible to artificially reduce an intervalbetween the two light emission points using a structure which is bothinexpensive and suited for mass-production.

A further object of the present invention is to provide an opticalrecording and/or reproducing apparatus for recording information onand/or reproducing information from a recording medium using a lightbeam, comprising an optical pickup which emits one of two light beamshaving mutually different wavelengths on the recording medium dependingon a type of the recording medium, and means for processing theinformation to be recorded on the recording medium prior to supplyingthe information to the optical pickup, and processing the informationreproduced from the recording medium and obtained from the opticalpickup, where said optical pickup has an optical module comprising afirst light source which emits a first light beam from a first lightemission point in a predetermined direction, a second light source whichemits a second light beam from a second light emission point in thepredetermined direction, and an optical element having a plurality ofreflection surfaces for reflecting the first and second light beams, andfinally outputting the first and second light beams in the predetermineddirection with a separation between the first and second light beamssmaller than a distance between the first and second light emissionpoints. According to the optical information recording and/orreproducing apparatus of the present invention, it is possible toartificially reduce an interval between the two light emission pointsusing a structure which is both inexpensive and suited formass-production.

Other objects and further features of the present invention will beapparent from the following detailed description when read inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing an optical module employing a methodproposed in a Japanese Laid-Open Patent Application No. 11-39684;

FIG. 2 is a plan view showing a first embodiment of an optical moduleaccording to the present invention;

FIG. 3 is a diagram for explaining an angle of radiation of a laser beamemitted from a semiconductor laser;

FIGS. 4A and 4B are diagrams for explaining an interval between twolight emission points;

FIG. 5 is a plan view showing a second embodiment of the optical moduleaccording to the present invention;

FIG. 6 is a perspective view showing the second embodiment of theoptical module;

FIG. 7 is a plan view showing a third embodiment of the optical moduleaccording to the present invention;

FIG. 8 is a perspective view showing the third embodiment of the opticalmodule;

FIG. 9 is a plan view showing a fourth embodiment of the optical moduleaccording to the present invention;

FIG. 10 is a perspective view showing the fourth embodiment of theoptical module;

FIG. 11 is a plan view showing a fifth embodiment of the optical moduleaccording to the present invention;

FIG. 12 is a perspective view showing the fifth embodiment of theoptical module;

FIG. 13 is a side view showing a sixth embodiment of the optical moduleaccording to the present invention;

FIG. 14 is a plan view showing a first modification of the sixthembodiment of the optical module;

FIG. 15 is a plan view showing a second modification of the sixthembodiment of the optical module;

FIG. 16 is a plan view showing a seventh embodiment of the opticalmodule according to the present invention;

FIG. 17 is a perspective view showing the seventh embodiment of theoptical module;

FIG. 18 is a plan view showing an eighth embodiment of the opticalmodule according to the present invention;

FIG. 19 is a perspective view showing the eighth embodiment of theoptical module;

FIG. 20 is a plan view showing a ninth embodiment of the optical moduleaccording to the present invention;

FIG. 21 is a perspective view showing the ninth embodiment of theoptical module;

FIG. 22 is a diagram for explaining reflections in the ninth embodiment;

FIG. 23 is a diagram for explaining reflection in a vicinity of an apexportion of the reflection surface;

FIG. 24 is a diagram for explaining reflection in the vicinity of theapex portion of the reflection surface;

FIG. 25 is a plan view showing a first modification of the ninthembodiment of the optical module;

FIG. 26 is a plan view showing a second modification of the ninthembodiment of the optical module; and

FIG. 27 is a diagram showing an embodiment of an optical recordingand/or reproducing apparatus according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A description will be given of embodiments of an optical moduleaccording to the present invention and an optical recording and/orreproducing apparatus according to the present invention, by referringto FIG. 2 and the subsequent drawings.

When employing a method of artificially reducing an interval between twolight emission points by using reflection surfaces, a most importantfactor is to align optical axes of two light beams after the reflection.In the prior art FIG. 1 described above, the reflection surfaces 32B and32C having the 45-degree inclination angle is required in order to alignthe optical axes of the two light beams emitted from the two confrontingsemiconductor lasers 34 and 36 after being reflected by the reflectionsurfaces 32B and 32C. Since the use of a single reflection surface willchange the direction of the optical axis of the light beam after thereflection, it was only possible to use reflection surfaces having aspecific inclination angle, such as the reflection surface 32B or 32Chaving the 45-degree inclination angle as in the case of the prior artFIG. 1.

But the present inventor has found that the above described limitationscan be eliminated by using two confronting reflection surfaces which aremutually parallel. In other words, the optical axis of the light beamwhich is incident to the two parallel confronting reflection surfaces,after being reflected two times, becomes perfectly parallel to theoptical axis of the incident light beam before being reflected. Byutilizing this operating principle of the present invention, it ispossible to use two parallel confronting reflection surfaces having anarbitrary inclination angle, and as long as the optical axes of the twoincident light beams to the two parallel confronting reflection surfacesbefore being reflected are mutually parallel, it is possible to make thetwo light beams after being reflected two times by the two parallelconfronting reflection surfaces to become mutually parallel.

FIG. 2 is a plan view showing a first embodiment of the optical moduleaccording to the present invention. The optical module shown in FIG. 2includes a semiconductor laser (or laser diode) 2-1 which emits a laserbeam having a wavelength of 650 nm, a semiconductor laser 2-2 whichemits a laser beam having a wavelength of 780 nm, and a sub-mountingmember 2-7 on which the semiconductor lasers 2-1 and 2-2 are provided.Reflection surfaces 2-3 are formed on the sub-mounting member 2-7.Optical axes of the laser beams output from the optical module aredenoted by a reference numeral 2-4.

Because the semiconductor lasers 2-1 and 2-2 are arranged parallel toeach other on the sub-mounting member 2-7, the optical axes of the laserbeams emitted from the semiconductor lasers 2-1 and 2-2 are mutuallyparallel before reaching the corresponding first reflection surfaces2-3. The optical axis of the laser beam emitted from the semiconductorlaser 2-1 and reflected two times, that is, reflected by the firstreflection surface 2-3 and the second reflection surface 2-3, isparallel to the optical axis of this laser beam before reaching thefirst reflection surface 2-3. Similarly, the optical axis of the laserbeam emitted from the semiconductor laser 2-2 and reflected two times,that is, reflected by the first reflection surface 2-3 and the secondreflection surface 2-3, is parallel to the optical axis of this laserbeam before reaching the first reflection surface 2-3. Therefore, theoptical axes 2-4 of the laser beams which are respectively reflected twotimes by the reflection surfaces 2-3 and output from the optical module,are mutually parallel. The reflection surface 2-3 may have an arbitraryinclination angle other than an angle perpendicular to or parallel tothe optical axis of the laser beams emitted from the semiconductorlasers 2-1 and 2-2. In addition, even if a relative angle between eachof the semiconductor lasers 2-1 and 2-2 and each of the reflectionsurfaces 2-3 includes a slight error, this error will not affect thedirection of the optical axes 2-4 of the laser beams after beingreflected by the reflection surfaces 2-3. For this reason, a relativelysimple and inexpensive mounting or assembling technique which does notrequire an extremely high accuracy and is suited for mass-production maybe used for the mounting or assembling of the optical module.

Therefore, according to this embodiment, it is possible to artificiallyvary an interval between two light emission points of two semiconductorlasers with ease, and realize an inexpensive optical module having areduced interval between the two light emission points.

The laser beam emitted from the semiconductor laser spreads about acenter of the optical axis, and an area required of the reflectionsurface becomes larger as a distance from the light emission point tothe reflection surface becomes larger. The interval between the lightemission points after the laser beams are reflected cannot be reduced tobecome smaller than the size of the reflection surface. For this reason,in order to reduce the interval between the two light emission points,it is necessary to reduce the distance between each light emission pointand the corresponding reflection surface.

In order to further reduce the distance between each light emissionpoint and each of the corresponding reflection surfaces in the structureshown in FIG. 2, the laser beam emitted from the semiconductor laser 2-1is first reflected by the first reflection surface 2-3 towards the othersemiconductor laser 2-2 and is further reflected by the secondreflection surface 2-3 to propagate along the optical axis 2-4.Similarly, the laser beam emitted from the semiconductor laser 2-2 isfirst reflected by the first reflection surface 2-3 towards the othersemiconductor laser 2-1 and is further reflected by the secondreflection surface 2-3 to propagate along the optical axis 2-4. Bytaking these measures, it is possible to further reduce the intervalbetween the two light emission points of the optical module.

The distance between each light emission point and each of thecorresponding reflection surfaces in the structure shown in FIG. 2 canbe minimized when the arrangement of the semiconductor laser 2-1 and thecorresponding first and second reflection surfaces 2-3 is symmetrical,with respect to the right and left about an imaginary center linepassing between the semiconductor lasers 2-1 and 2-2 and extending inthe direction in which the laser beams are output from the opticalmodule in FIG. 2, to the arrangement of the semiconductor laser 2-2 andthe corresponding first and second reflection surfaces 2-3. In thiscase, it is possible to realize an optical module in which the intervalbetween the two light emission points is extremely small.

The laser beam emitted from the semiconductor laser has an angle ofradiation which is dependent on the optical structure of a lightemission part. The angle of radiation of the laser beam emitted from thesemiconductor laser greatly differs between a direction parallel to anda direction perpendicular to a mounting surface of the semiconductorlaser (hereinafter simply referred to as a laser mounting surface). Inthe semiconductor laser which has the general index waveguide structureand is used in optical disk drives, the angle of radiation of theemitted laser beam is flat and approximately 10 degrees in the directionparallel to the laser mounting surface and is approximately 25 degreesin the direction perpendicular to the laser mounting surface. Hence, thelaser beam has an oval cross sectional shape which is elongated in thedirection perpendicular to the laser mounting surface, as shown in FIG.3. FIG. 3 is a diagram for explaining the angle of radiation of thelaser beam emitted from the semiconductor laser 2-1 or 2-3.

Particularly in the case of the blue semiconductor laser which isrecently being developed, structure optimization for use in the opticalpickup has not made considerable progress. In the case of the bluesemiconductor laser, the angle of radiation becomes extremely flat suchthat the angle is approximately 5 degrees in the direction parallel tothe laser mounting surface and is approximately 30 degrees in thedirection perpendicular to the laser mounting surface. In a case wherethe distance from the light emission point of the semiconductor laserand the reflection surface is constant, an interval “b” between the twolight emission points in an arrangement shown in FIG. 4B where an angleformed between the laser mounting surface and the reflection surface isapproximately 90 degrees is smaller than an interval “a” between the twolight emission points in an arrangement shown in FIG. 4A. FIGS. 4A and4B are diagrams for explaining the interval between two light emissionpoints. In FIGS. 4A and 4B, a laser beam spot is indicated by thehatching. In FIGS. 4A and 4B, those parts which are the same as thosecorresponding parts in FIG. 2 are designated by the same referencenumerals, and a description thereof will be omitted.

Hence, in this embodiment of the optical module, all of the reflectionsurfaces 2-3 formed on the sub-mounting member 2-7 shown in FIG. 2 areapproximately perpendicular to the laser mounting surface, that is, thesurfaces of the semiconductor lasers 2-1 and 2-2. As a result, it ispossible to realize an optical module in which the interval between thetwo light emission points is minimized.

It is desirable that each pair of confronting reflection surfaces 2-3are mutually parallel and that each pair of confronting reflectionsurfaces 2-3 can be produced at a low cost. Hence, a material which ismost suited for forming the reflection surfaces 2-3 and satisfying theseconditions is single crystal silicon (Si). Specific crystal faces of thesingle crystal Si can be obtained selectively by carrying out ananisotropic etching using an etchant such as KOH. A <111> face of thesingle crystal Si is extremely suited for use as the reflection surface2-3 which is highly accurate. The selection ratio of the <111> face ofthe single crystal Si is 100 or greater when the anisotropic etching iscarried out. Hence, it is possible to selectively obtain the crystalface which is usable as the reflection surface 2-3 using the singlecrystal Si. In addition, it is possible to easily form the pair ofconfronting reflection surfaces 2-3 are mutually parallel at a low cost,utilizing the processes used to form semiconductor devices. Furthermore,since Si has a high thermal conductivity, Si may also be used for thesub-mounting member 2-7 on which the semiconductor lasers 2-1 and 2-2are integrally formed.

Accordingly, it is possible to easily form the sub-mounting member 2-7having the pairs of confronting reflection surfaces 2-3 which aremutually parallel with a high accuracy and at a low cost. When using anon-conductor material for the sub-mounting member 2-7, it is desirableto use a high-resistance Si substrate normally having a conductivity ofapproximately 1000 Ωcm or greater.

When forming the sub-mounting member 2-7 from Si, it is possible to formall of the reflection surfaces 2-3 in one anisotropic etching by makingall of the reflection surfaces 2-3 from the <111> face of Si. In thiscase, it is possible to easily form at a low cost the sub-mountingmember 2-7 having pairs of the reflection surfaces 2-3 which aremutually parallel with a high accuracy and are approximatelyperpendicular to the laser mounting surface.

When forming all of the reflection surfaces 2-3 from the <111> face ofSi, the laser mounting surface which is approximately perpendicular toall of the reflection surfaces 2-3 can be formed from the <110> face ofSi, using the crystallographic properties of Si. In this case, it ispossible to form with ease and at a low cost the sub-mounting member 2-7which has the pairs of confronting reflection surfaces 2-3 which aremutually parallel and are approximately perpendicular to the lasermounting surface.

When the laser mounting surface of the sub-mounting member 2-7 is formedfrom the <110> face of Si, the <111> faces of Si which appear bycarrying out the anisotropic etching include the <111> face which isperpendicular to the <110> face forming the laser mounting surface, andalso the <111> face which forms an angle of 35.5 degrees with respect tothe <110> face. For this reason, it is important from the point of thedesign to determine how the <111> faces should be processed. Because theangle of radiation of the semiconductor laser is approximately 25 to 30degrees in the direction perpendicular to the laser mounting surface,the inclination direction of the <111> face and the light emittingdirection of the semiconductor laser should be aligned so that the laserbeam emitted from the semiconductor laser will not be kicked. In otherwords, since the <111> face having an angle of 35.3 degrees to the lasermounting surface is inclined in the normal direction of the <100> facewhich is perpendicular to the <110> face, the semiconductor laser shouldbe mounted so that the laser beam is emitted therefrom towards the <111>face.

Therefore, it is possible to easily produce at a low cost thesub-mounting member 2-7 having the pairs of confronting reflectionsurfaces 2-3 which are mutually parallel with a high accuracy and areapproximately perpendicular to the laser mounting surface.

As described before in conjunction with the prior art, it is necessaryto use two semiconductor lasers, one emitting a laser beam having awavelength of 780 nm and another emitting a laser beam having awavelength of 650 nm, in order to record information on and/or reproduceinformation from the CD-R and the DVD on a single optical recordingand/or reproducing apparatus. When this embodiment of the optical moduleuses the two semiconductor lasers respectively emitting the laser beamshaving the wavelengths of 780 nm and 650 nm as the semiconductor lasers2-1 and 2-2 shown in FIG. 2, it is possible to realize a light sourcewhich emits light beams having two different wavelengths and in whichthe interval between the two light emission points is extremely small,by use of two ordinary semiconductor lasers (laser diodes) which arearranged adjacent to each other or, arranged side by side to each other.

Next, a description will be given of a second embodiment of the opticalmodule according to the present invention, by referring to FIGS. 5 and6. FIG. 5 is a plan view showing this second embodiment of the opticalmodule, and FIG. 6 is a perspective view showing the optical moduleshown in FIG. 5.

The optical module shown in FIGS. 5 and 6 includes a semiconductor laser(or laser diode) 5-1 which emits a laser beam having a wavelength of 650nm, a semiconductor laser 5-2 which emits a laser beam having awavelength of 780 nm, and a sub-mounting member 5-7 on which thesemiconductor lasers 5-1 and 5-2 are provided. Reflection surfaces 5-3are formed on the sub-mounting member 2-7. An optical axis of each ofthe laser beams output from the optical module is denoted by a referencenumeral 5-5, and a spread of each of the laser beams output from theoptical module is denoted by a reference numeral 5-6.

Because the semiconductor lasers 5-1 and 5-2 are arranged parallel toeach other on a laser mounting surface of the sub-mounting member 5-7,the optical axes of the laser beams emitted from the semiconductorlasers 5-1 and 5-2 are mutually parallel before reaching thecorresponding first reflection surfaces 5-3. The optical axis of thelaser beam emitted from the semiconductor laser 5-1 and reflected twotimes, that is, reflected by the first reflection surface 5-3 and thesecond reflection surface 5-3, is parallel to the optical axis of thislaser beam before reaching the first reflection surface 5-3. Similarly,the optical axis of the laser beam emitted from the semiconductor laser5-2 and reflected two times, that is, reflected by the first reflectionsurface 5-3 and the second reflection surface 5-3, is parallel to theoptical axis of this laser beam before reaching the first reflectionsurface 5-3. Therefore, the optical axes 5-5 of the laser beams whichare respectively reflected two times by the reflection surfaces 5-3 andoutput from the optical module via a cutout 5-8 shown in FIG. 6, aremutually parallel. The cutout 5-8 is provided to permit output of thelaser beams from the optical module.

The sub-mounting member 5-7 is made of single crystal Si, and the lasermounting surface is formed by the <110> face of the Si. In addition, thereflection surfaces 5-3 are formed symmetrically with respect to theright and left in FIG. 5, by the <111> faces of the Si. Each of thesemiconductor lasers 5-1 and 5-2 are mounted on the laser mountingsurface in a direction so that the laser beam is emitted in a directionalong the normal direction to the <100> face which is perpendicular tothe <110> face forming the laser mounting surface. An interval betweenartificial light emission points of the two laser beams after thereflections is considerably small compared to an interval between lightemission points 5-4 of the two semiconductor lasers 5-1 and 5-2, and itis possible to obtain the same effects as in the case of the firstembodiment of the optical module described above.

The laser beam emitted from the semiconductor laser spreads about acenter of the optical axis, and an area required of the reflectionsurface becomes larger as a distance from the light emission point tothe reflection surface becomes larger. The interval between the lightemission points after the laser beams are reflected cannot be reduced tobecome smaller than the size of the reflection surface. For this reason,in order to reduce the interval between the two light emission points,it is necessary to reduce the distance between each light emission pointand the corresponding reflection surface.

The distance between the light emission point and the correspondingreflection surface is dependent on the distance from the light emissionpoint to an end portion of the semiconductor laser. Accordingly, adescription will now be given of a third embodiment of the opticalmodule in which the distance from the light emission point to the endportion of the semiconductor laser is reduced, so as to reduce thedistance between the light emission point and the correspondingreflection surface.

FIG. 7 is a plan view showing the third embodiment of the optical moduleaccording to the present invention, and FIG. 8 is a perspective viewshowing the optical module shown in FIG. 7.

The optical module shown in FIGS. 7 and 8 includes a semiconductor laser(or laser diode) 7-1 which emits a laser beam having a wavelength of 650nm, a semiconductor laser 7-2 which emits a laser beam having awavelength of 780 nm, and a sub-mounting member 7-7 on which thesemiconductor lasers 7-1 and 7-2 are provided. Reflection surfaces 7-3are formed on the sub-mounting member 7-7. An optical axis of each ofthe laser beams output from the optical module is denoted by a referencenumeral 7-5, and a spread of each of the laser beams output from theoptical module is denoted by a reference numeral 7-6.

Because the semiconductor lasers 7-1 and 7-2 are arranged parallel toeach other on a laser mounting surface of the sub-mounting member 7-7,the optical axes of the laser beams emitted from the semiconductorlasers 7-1 and 7-2 are mutually parallel before reaching thecorresponding first reflection surfaces 7-3. The optical axis of thelaser beam emitted from the semiconductor laser 7-1 and reflected twotimes, that is, reflected by the first reflection surface 7-3 and thesecond reflection surface 7-3, is parallel to the optical axis of thislaser beam before reaching the first reflection surface 7-3. Similarly,the optical axis of the laser beam emitted from the semiconductor laser7-2 and reflected two times, that is, reflected by the first reflectionsurface 7-3 and the second reflection surface 7-3, is parallel to theoptical axis of this laser beam before reaching the first reflectionsurface 7-3. Therefore, the optical axes 7-5 of the laser beams whichare respectively reflected two times by the reflection surfaces 7-3 andoutput from the optical module via a cutout 7-8 shown in FIG. 8, aremutually parallel. The cutout 7-8 is provided to permit output of thelaser beams from the optical module.

The sub-mounting member 7-7 is made of single crystal Si, and the lasermounting surface is formed by the <110> face of the Si. In addition, thereflection surfaces 7-3 are formed symmetrically with respect to theright and left in FIG. 7, by the <111> faces of the Si. Each of thesemiconductor lasers 7-1 and 7-2 are mounted on the laser mountingsurface in a direction so that the laser beam is emitted in a directionalong the normal direction to the <100> face which is perpendicular tothe <110> face forming the laser mounting surface. An interval betweenartificial light emission points of the two laser beams after thereflections is considerably small compared to an interval between lightemission points 7-4 of the two semiconductor lasers 7-1 and 7-2, and itis possible to obtain the same effects as in the case of the firstembodiment of the optical module described above. Furthermore, since thelight emission points 7-4 are respectively arranged at the mutuallyneighboring end portions of the semiconductor lasers 7-1 and 7-2, theinterval between the light emission points 7-4 is small compared to theinterval between the light emission points 6-4 of the second embodimentshown in FIGS. 5 and 6. As a result, it is possible to obtain the sameeffects as in the case of the second embodiment of the optical moduledescribed above, and moreover, the interval between artificial lightemission points of the two laser beams after the reflections can be madeconsiderably smaller than that of the second embodiment.

FIG. 9 is a plan view showing the fourth embodiment of the opticalmodule according to the present invention, and FIG. 10 is a perspectiveview showing the optical module shown in FIG. 9. In FIGS. 9 and 10,those parts which are the same as those corresponding parts in FIGS. 5and 6 are designated by the same reference numerals, and a descriptionthereof will be omitted.

In FIGS. 9 and 10, an optical element 13 includes a first pair ofconfronting reflection surfaces 5-3 which are mutually parallel and arenon-perpendicular and non-parallel to the optical axis of the laser beamemitted from the semiconductor laser 5-1, and a second pair ofconfronting reflection surfaces 5-3 which are mutually parallel and arenon-perpendicular and non-parallel to the optical axis of the laser beamemitted from the semiconductor laser 5-2. The semiconductor lasers 5-1and 5-2, and the optical element 13 are mounted on the sub-mountingmember 5-7. According to this fourth embodiment, it is possible toobtain the same effects as the second embodiment described above.

FIG. 11 is a plan view showing the fifth embodiment of the opticalmodule according to the present invention, and FIG. 12 is a perspectiveview showing the optical module shown in FIG. 11. In FIGS. 11 and 12,those parts which are the same as those corresponding parts in FIGS. 9and 10 are designated by the same reference numerals, and a descriptionthereof will be omitted.

In FIGS. 11 and 12, an optical element 23 includes a first pair ofconfronting reflection surfaces 7-3 which are mutually parallel and arenon-perpendicular and non-parallel to the optical axis of the laser beamemitted from the semiconductor laser 7-1, and a second pair ofconfronting reflection surfaces 7-3 which are mutually parallel and arenon-perpendicular and non-parallel to the optical axis of the laser beamemitted from the semiconductor laser 7-2. The semiconductor lasers 7-1and 7-2, and the optical element 23 are mounted on the sub-mountingmember 7-7. According to this fifth embodiment, it is possible to obtainthe same effects as the third embodiment described above.

Next, a description will be given of a sixth embodiment of the opticalmodule according to the present invention, by referring to FIG. 13. FIG.13 is a side view showing the sixth embodiment of the optical module. InFIG. 13, those parts which are the same as those corresponding parts inFIGS. 9 and 10 are designated by the same reference numerals, and adescription thereof will be omitted.

As shown in FIG. 13, this sixth embodiment is provided with a stem 15,so as to facilitate the positioning of the elements forming the opticalmodule. The sub-mounting member 5-7 is mounted on a top surface (rightside in FIG. 13) of the stem 15, and the semiconductor lasers 5-1 and5-2 are mounted on the laser mounting surface (right side in FIG. 13) ofthe sub-mounting member 5-7. A side surface (top side in FIG. 13) of thestem 15 is approximately perpendicular to the laser mounting surface,and the optical element 13 is mounted on this side surface (top side inFIG. 13) of the stem 15. When considering the ease with which the weightof the optical element 13 may be applied, it is desirable to mount theoptical element 13 on the side surface of the stem 15 which isapproximately perpendicular to the top surface of the stem 15 on whichthe sub-mounting member 5-7 is mounted. In FIG. 13, X denotes adirection which is perpendicular to the laser mounting surface.

An arrangement which enables the size of the reflection surfaces 5-3 ina direction perpendicular to the laser mounting surface to be minimizedis to arrange the optical axis of each laser beam in a vicinity of acenter of the corresponding reflection surface 5-3.

When the <111> face of the single crystal Si is used to form eachreflection surface 5-3, this <111> face is perpendicular to the lasermounting surface. In order to realize the reflection surfaces 5-3 at alow cost, it is desirable to use a single crystal Si substrate having asubstrate surface formed by the <110> face. In this case, the <111> facewhich is perpendicular to the <110> substrate surface is obtained in twodirections, and further, the <110> substrate surface is parallel to thelaser mounting surface.

The two <111> faces, which are perpendicular to the <110> substratesurface, intersect at an angle of 70.52 (180−70.52=109.48) degrees. Inorder to arrange the <111> faces symmetrically with respect to the rightand left in the plan view of the optical module, it is possible to usethe <110> face or the <100> face as a mounting surface of the opticalelement 13 which is mounted on the side surface of the stem 15. The two<111> faces which are perpendicular to the <110> substrate surfaceintersect at the angle of 109.48 degrees when the <110> face is used asthe mounting surface of the optical element 13. On the other hand, thetwo <111> faces which are perpendicular to the <110> substrate surfaceintersect at the angle of 70.52 degrees when the <100> face is used asthe mounting surface of the optical element 13.

FIG. 14 is a plan view showing a first modification of the sixthembodiment of the optical module, where the <110> face is used as themounting surface of the optical element 13 with respect to the stem 15.On the other hand, FIG. 15 is a plan view showing a second modificationof the sixth embodiment of the optical module, where the <100> face isused as the mounting surface of the optical element 13 with respect tothe stem 15. In FIGS. 14 and 15, those parts which are the same as thosecorresponding parts in FIGS. 9 and 10 are designated by the samereference numerals, and a description thereof will be omitted.

As may be seen from a comparison of FIGS. 14 and 15, an increase in theoptical path at the optical element 13 is smaller for the secondmodification shown in FIG. 15. It is desirable that the increase in theoptical path is as small as possible in an optical system whichconverges the light beam on a light receiving element using a hologramelement such as that used in the optical pickup, because the increase inthe optical path may restrict the degree of freedom of design. For thisreason, it is more desirable for the mounting surface of the opticalelement 13 to be formed by the <100> face of the single crystal Si whenreducing the length of the optical path.

Next, a description will be given of a seventh embodiment of the opticalmodule according to the present invention, by referring to FIGS. 16 and17. FIG. 16 is a plan view showing the seventh embodiment of the opticalmodule, and FIG. 17 is a perspective view showing the seventh embodimentof the optical module. In FIGS. 16 and 17, those parts which are thesame as those corresponding parts in FIGS. 9, 10 and 13 are designatedby the same reference numerals, and a description thereof will beomitted.

In FIGS. 16 and 17, the optical element 13 and the sub-mounting member5-7 are made of a single crystal Si. Each of the reflection surfaces 5-3of the optical element 13 is formed by the <111> face of the Si, and thelaser mounting surface of the sub-mounting member 5-7 is formed by the<100> face of the Si. In addition, the surface of the optical element 13perpendicular to the laser mounting surface is formed by the <110> faceof the Si. According to this seventh embodiment, it is possible toobtain the same effects as the fourth embodiment described above.

Next, a description will be given of an eighth embodiment of the opticalmodule according to the present invention, by referring to FIGS. 18 and19. FIG. 18 is a plan view showing the eighth embodiment of the opticalmodule, and FIG. 19 is a perspective view showing the eighth embodimentof the optical module. In FIGS. 18 and 19, those parts which are thesame as those corresponding parts in FIGS. 11, 12 and 13 are designatedby the same reference numerals, and a description thereof will beomitted.

In FIGS. 18 and 19, the optical element 23 and the sub-mounting member7-7 are made of a single crystal Si. Each of the reflection surfaces 7-3of the optical element 23 is formed by the <111> face of the Si, and thelaser mounting surface of the sub-mounting member 7-7 is formed by the<100> face of the Si. In addition, the surface of the optical element 23perpendicular to the laser mounting surface is formed by the <110> faceof the Si. According to this eighth embodiment, it is possible to obtainthe same effects as the fifth embodiment described above.

In each of the embodiments and modifications described above, the secondreflection surfaces meet and form a triangular shape in the plan view ofthe optical module. But at an apex portion of this triangular shape, onthe order of several tens of μm from the apex, it is difficult to obtaina high processing accuracy and the surface accuracy of the reflectionsurface may deteriorate at the apex portion. If the laser beam isreflected at the apex portion of the reflection surface having thedeteriorated surface accuracy, the laser beam may be deflected inunwanted directions and generate noise. In addition, even if the surfaceaccuracy at the apex portion of the reflection surfaces can bemaintained high, the laser beam reflected at the apex portion may stillscatter due to diffraction and similarly generate noise.

Accordingly, a description will now be given of a ninth embodiment ofthe optical module according to the present invention which canpositively prevent the generation of such noise, by referring to FIGS.20 through 24. FIG. 20 is a plan view showing the ninth embodiment ofthe optical module, and FIG. 21 is a perspective view showing the ninthembodiment of the optical module. FIG. 22 is a diagram for explainingreflections in the ninth embodiment. Further, FIGS. 23 and 24 arediagrams for explaining reflection in a vicinity of an apex portion ofthe reflection surface. In FIGS. 20 through 24, those parts which arethe same as those corresponding parts in FIGS. 5, 6, 16 and 17 aredesignated by the same reference numerals, and a description thereofwill be omitted.

As shown in FIG. 22, the optical element 13 includes a pair of firstreflection surfaces 531, a pair of second reflection surfaces 532, and apair of tapered surfaces 533 forming an apex portion of a triangularshape formed by the second reflection surfaces 532. An inclination angleof each of the pair of tapered surfaces 533 is different from that ofthe second reflection surfaces 532. The first and second reflectionsurfaces 531 and 532 provided on the left side in FIG. 22 confront eachother and are mutually parallel. Similarly, the first and secondreflection surfaces 531 and 532 on the right side in FIG. 22 confronteach other and are mutually parallel.

For example, between the first and second reflection surfaces 531 and532 on the left side in FIG. 22, a normal to the first reflectionsurface 531 is parallel to a normal to the second reflection surface 532because the first and second reflection surfaces 531 and 532 aremutually parallel. Accordingly, if the incident angle and the exit angleof the laser beam is defined by intersection angles with respect to thenormal, the incident angle of the laser beam to the first reflectionsurface 531 and the exit angle of the laser beam from the firstreflection surface 531 are equal. Similarly, the incident angle of thelaser beam to and the exit angle of the laser beam from the secondreflection surface 532 are equal. The exit angle of the laser beam fromthe first reflection surface 531 and the incident angle of the laserbeam to the second reflection surface 532 are equal since these anglesare alternate angles. For this reason, the incident angle of the laserbeam to the first reflection surface 531 and the exit angle of the laserbeam from the second reflection surface 532 are also equal. Because thenormal to the first reflection surface 531 and the normal to the secondreflection surface 532 are mutually parallel, the optical axis of thelaser beam emitted from the corresponding semiconductor laser 5-1 isparallel to the optical axis 5-5 of the laser beam output from theoptical module.

The tapered surfaces 533 are obtained by removing a portion of theintersecting second reflection surfaces 532 at the apex portion of thetriangular shape. As shown in FIG. 22 with respect to the laser beamemitted from the left semiconductor laser 5-1, the spread 5-6 of thelaser beam is caused by the peripheral light due to diffraction of lightabout the optical axis. The tapered surfaces 533 are provided in orderto prevent the peripheral light from reaching an unwanted location on arecording surface of a recording medium to generate noise when theoptical module is used in the optical pickup of the optical recordingand/or reproducing apparatus.

FIG. 23 shows a case where the apex portion of the triangular shape atthe intersection of the second reflection surfaces 532 projects due to alimit in the processing accuracy. On the other hand, FIG. 24 shows acase where the apex portion of the triangular shape at the intersectionof the second reflection surfaces 532 is tapered by the tapered surfaces533, as in the case of this ninth embodiment. In FIGS. 23 and 24, CBdenotes a center light portion of the laser beam, and PB denotes aperipheral light portion of the laser beam.

As shown in FIG. 23, the projecting apex portion reflects the peripherallight portion PB, and causes the peripheral light to propagate in anunwanted direction together with the center light portion CB of thelaser beam. The peripheral light portion PB generates noise whenirradiated at an unwanted location of the recording surface of therecording medium. But in the case shown in FIG. 24, the peripheral lightportion PB is reflected by the tapered surface 533 in a direction otherthan the propagating direction of the center light portion CB of thelaser beam. For this reason, the arrangement shown in FIG. 24 canpositively prevent the noise which would be generated if the peripherallight portion PB were to propagate towards the recording surface of therecording medium together with the center light portion CB of the laserbeam. A light blocking means such as a light blocking plate (not shown)may be provided at a position in a path intercepting the reflectedperipheral light portion PB from the tapered surface 533, so as to morepositively prevent the reflected peripheral light portion PB fromreaching an unwanted location such as the unwanted location on therecording surface of the recording medium.

FIG. 25 is a plan view showing a first modification of the ninthembodiment of the optical module, where the <110> face is used as themounting surface of the optical element 13 with respect to the stem 15,similarly to the structure shown in FIG. 14. On the other hand, FIG. 26is a plan view showing a second modification of the ninth embodiment ofthe optical module, where the <100> face is used as the mounting surfaceof the optical element 13 with respect to the stem 15, similarly to thestructure shown in FIG. 15. In FIGS. 25 and 26, those parts which arethe same as those corresponding parts in FIGS. 20, 21 and 22 aredesignated by the same reference numerals, and a description thereofwill be omitted.

As may be seen from a comparison of FIGS. 25 and 26, an increase in theoptical path at the optical element 13 is smaller for the secondmodification shown in FIG. 26. It is desirable that the increase in theoptical path is as small as possible in an optical system whichconverges the light beam on a light receiving element using a hologramelement such as that used in the optical pickup, because the increase inthe optical path may restrict the degree of freedom of design. For thisreason, it is more desirable for the mounting surface of the opticalelement 13 to be formed by the <100> face of the single crystal Si whenreducing the length of the optical path.

FIG. 27 is a diagram showing an embodiment of an optical recordingand/or reproducing apparatus according to the present invention. Asshown in FIG. 27, the optical recording and/or reproducing apparatusincludes an optical pickup 501, a write channel 52, a read channel, anda motor 504. The motor 504 rotates an optical recording medium 505, suchas a disk, which is loaded into the optical recording and/or reproducingapparatus, by a known means. This basic structure of the opticalrecording and/or reproducing apparatus is known, and other known basicstructures may be used for the optical recording and/or reproducingapparatus.

This embodiment of the optical recording and/or reproducing apparatus ischaracterized by an optical module 510 provided within the opticalpickup 501. The optical module 510 may have the structure of any of theembodiments and modifications of the optical module described above.

In a write mode of the optical recording and/or reproducing apparatus, awrite instruction from a host unit (not shown) such as a personalcomputer causes a write data from the host unit to be processed in thewrite channel 502 and supplied to the optical pickup 501. The opticalpickup 501 irradiates a laser beam which is emitted from the opticalmodule 501 on the optical recording medium 505, depending on the type ofthe optical recording medium 505, so as to record the write data on theoptical recording medium. For example, if the optical recording medium505 is a CD-ROM, the laser beam having the wavelength of 780 nm isirradiated on the optical recording medium 505.

On the other hand, in a read mode of the optical recording and/orreproducing apparatus, a read instruction from the host unit causes theoptical pickup 501 to irradiate a laser beam which is emitted from theoptical module 501 on the optical recording medium 505, depending on thetype of the optical recording medium 505, so as to reproduce read datafrom the optical recording medium. For example, if the optical recordingmedium 505 is a DVD, the laser beam having the wavelength of 650 nm isirradiated on the optical recording medium 505. The read instructionalso causes the read data from the optical pickup 501 to be processed inthe read channel 502 and supplied to the host unit.

According to this embodiment of the optical recording and/or reproducingapparatus, it is possible to realize an inexpensive optical recordingand/or reproducing apparatus which is compatible with a plurality oftypes of recording media which require light beams having differentwavelengths to be irradiated thereon for the data recording and/or datareproduction.

Any of the embodiments and modifications of the optical module describedabove may be combined with a hologram element, photodiode chip or thelike to form an integrated optical pickup module having an extremelysmall interval between two light emission points from which two lightbeams are emitted. Such an integrated optical pickup module can beproduced by a relatively simple process at a low cost. The two lightbeams emitted from the two light emission points may have mutuallydifferent wavelengths such as 780 nm and 650 nm or, 650 nm and 410 nm.

In addition, since the reflection surface formed by the Si has arelatively low reflectivity, it is desirable in each of the embodimentsand modifications described above to provide a reflection layer on thereflection surface in order to increase the reflectivity. The incidentangle of the laser beam with respect to the reflection surface isapproximately ±10 degrees when the spread of the laser beam is takeninto consideration, for example, and is relatively large. But it isextremely difficult to obtain a high reflectivity with respect to such alarge incident angle using a dielectric multi-layer structure.

Gold (Au) has a higher reflectivity with respect to the wavelength of650 nm to wavelengths of the near infrared region than aluminum (Al),and is extremely suited for use as the reflection layer to be formed onthe reflection surface. Since the bonding strength of Au on Si is small,however, it is desirable to employ a multi-layer structure in which theAu layer is formed on an underlayer which is made of titanium (Ti),chromium (Cr) or the like. By employing such a multi-layer structure forthe reflection layer on the reflection surface, it is possible to obtaina high reflectivity and a large bonding strength between the reflectionlayer and the Si underneath. Of course, the reflection layer may beprovided on all of the reflection surfaces or only on selectedreflection surfaces.

Further, the present invention is not limited to these embodiments, butvarious variations and modifications may be made without departing fromthe scope of the present invention.

1. An optical module comprising: a first light source which emits afirst light beam from a first light emission point in a predetermineddirection; a second light source which emits a second light beam from asecond light emission point in the predetermined direction; and anoptical element having a plurality of reflection surfaces for reflectingthe first and second light beams, and finally outputting the first andsecond light beams in the predetermined direction with a separationbetween the first and second light beams smaller than a distance betweenthe first and second light emission points. 2-16. (canceled)
 17. Theoptical module as claimed in claim 1, wherein said optical element has acutout through which the first and second light beams are output fromthe optical module.
 18. The optical module as claimed in claim 1,wherein the first and second light beams are reflected at approximatecenters of each of the plurality of reflection surfaces.
 19. The opticalmodule as claimed in claim 1, wherein the first and second light beamsemitted from the first and second light sources have mutually differentwavelengths.
 20. The optical module as claimed in claim 19, wherein saidfirst and second light sources are made of semiconductor lasers.
 21. Theoptical module as claimed in claim 1, wherein the first light emissionpoint is provided at a position on the first light source closer to anend of the first light source adjacent to the second light source, andthe second light emission point is provided at a position on the secondlight source closer to an end of the second light source adjacent to thefirst light source.
 22. The optical module as claimed in claim 1,wherein at least some of the plurality of reflection surfaces have areflection layer with a multi-layer structure provided thereon, saidmulti-layer structure comprising an Au layer is formed on an underlayerwhich is in contact with the reflection surface.
 23. The optical moduleas claimed in claim 22, wherein the underlayer is made of a materialselected from a group consisting of Ti and Cr.
 24. The optical module asclaimed in claim 1, further comprising: a stem having first and secondsurfaces which are mutually adjacent; a sub-mounting member having amounting surface on which the first and second light sources aremounted, and an opposite surface provided on an opposite end from themounting surface, said opposite surface of the sub-mounting member beingconnected to the first surface of the stem, said optical element beingconnected to the second surface of the stem.
 25. The optical module asclaimed in claim 1, wherein the plurality of reflection surfacesinclude: a first pair of confronting reflection surfaces which aremutually parallel and included by a predetermined angle with respect toan optical axis of the first light beam emitted from the first lightsource; a second pair of confronting reflection surfaces which aremutually parallel and included by a predetermined angle with respect toan optical axis of the second light beam emitted from the second lightsource, and one of said first pair of confronting reflection surfacesand one of said second pair of confronting reflection surfaces formingintersecting reflection surfaces which intersect at an apex portion ofan approximately triangular shape formed by the intersecting reflectionsurfaces, said apex portion having a pair of tapered surfaces having aninclination different from that of the intersecting reflection surfaces.26. The optical module as claimed in claim 25, wherein the intersectingreflection surfaces reflect center light portions of the first andsecond light beams in the predetermined direction, and the taperedsurfaces reflect peripheral light portions of the first and second lightbeams in a direction other than the predetermined direction.
 27. Anoptical recording and/or reproducing apparatus for recording informationon and/or reproducing information from a recording medium using a lightbeam, comprising: an optical pickup which emits one of two light beamshaving mutually different wavelengths on the recording medium dependingon a type of the recording medium; and means for processing theinformation to be recorded on the recording medium prior to supplyingthe information to the optical pickup, and processing the informationreproduced from the recording medium and obtained from the opticalpickup, said optical pickup having an optical module comprising: a firstlight source which emits a first light beam from a first light emissionpoint in a predetermined location; a second light source which emits asecond light beam from a second light emission point in thepredetermined direction; and an optical element having a plurality ofreflection surfaces for reflecting the first and second light beams, andfinally outputting the first and second light beams in the predetermineddirection with a separation between the first and second light beamssmaller than a distance between the first and second light emissionpoints.
 28. The optical recording and/or reproducing apparatus asclaimed in claim 27, wherein the plurality of reflection surfaces of theoptical module include: a first pair of confronting reflection surfaceswhich are mutually parallel and are non-perpendicular and non-parallelwith respect to an optical axis of the first light beam emitted from thefirst light source; and a second pair of confronting reflection surfaceswhich are mutually parallel and non-perpendicular and non-parallel withrespect to an optical axis of the second light beam emitted from thesecond light source.
 29. The optical recording and/or reproducingapparatus as claimed in claim 28, wherein: the first pair of confrontingreflection surfaces is made up of a reflection surface which firstreflects the first light beam from the first light source in a directioncloser to the second light source, and a reflection surface which thenreflects the first light beam in a direction away from the first lightsource; and the second pair of confronting reflection surfaces is madeup of a reflection surface which first reflects the second light beamfrom the second light source in a direction closer to the first lightsource, and a reflection surface which then reflects the second lightbeam in a direction away from the second light source.
 30. The opticalrecording and/or reproducing apparatus as claimed in claim 27, wherein:the plurality of reflection surfaces include a first pair of confrontingreflection surfaces which are provided with respect to the first lightbeam, and a second pair of confronting reflection surfaces which areprovided with respect to the second light beam; and an arrangement ofthe first light source and the first pair of confronting reflectionsurfaces and an arrangement of the second light source and the secondpair of confronting reflection surfaces are symmetrical about animaginary center line passing between the first and second light sourcesand extending in the predetermined direction.